Biohydrogen production by biological water-gas shift reaction and bioelectrochemical systems

Numerous strategies have been suggested to address the issue of global warming, which should be prioritized. Due to the availability of effective outcomes via well-established biotechnological applications, current developments have shown the benefits and superiority of nontraditional techniques for more sustainable bioprocessing. Several mesophilic and thermophilic bacteria have reported a distinct fermentation route using C1 gases (e.g. CO and CO2) frequently found in waste gas streams or syngas to generate bio commodities such as acetic acid, ethanol, butanol, 2,3-Butanediol, and hydrogen. This chapter discusses the aforementioned unconventional technologies, which include hydrogen generation technologies such as biological water-gas shift process and microbial electrolysis. Additional details on these technologies, including the effect of microbial community selection on metabolic pathways, the role of bioreactor design in enhancing liquid-gas mass transfer, process parameters, direct and mediated electron transfer mechanisms, and the characteristics of membranes that contribute to improved conductivity and stability under dynamic process conditions. Future prospects include the adaption of different process parameters and materials, such as biochar incorporation into fermentation, and the integration of technologies into bioelectrochemical systems in order to develop a more sustainable method of hydrogen generation.